The Carbon Cycle
Aligned to HS-LS2-5 — Next Generation Science Standards.
What this lesson teaches
Carbon moves among living things, the air, water, and rock. Photosynthesis and respiration swap it with the atmosphere, oceans dissolve it, and rocks store it for long ages.
Worked examples
Example 1
Carbon in atmospheric carbon dioxide dissolves into the ocean, is built into a shell by a clam, and after the clam dies becomes limestone rock stored for millions of years.
Example 2
Burning coal returns carbon to the air that was removed from it 300 million years ago — the cycle running backwards, fast.
Example 3
The ocean holds far more carbon than the atmosphere, which is why a small change in how much it absorbs matters so much.
Practice questions
- List the four reservoirs where carbon is stored.
- Diagram a path for one carbon atom to move from the air into a rock.
- Explain how burning fossil fuels shifts carbon between reservoirs faster than natural processes.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
El ciclo del carbono
El carbono se mueve entre los seres vivos, el aire, el agua y las rocas. La fotosíntesis y la respiración lo intercambian con la atmósfera, los océanos lo disuelven y las rocas lo almacenan durante largas eras.
Ejemplo 1: El carbono del dióxido de carbono atmosférico se disuelve en el océano, una almeja lo incorpora a su concha y, cuando la almeja muere, se convierte en roca caliza almacenada durante millones de años.
Ejemplo 2: Quemar carbón devuelve al aire carbono que se le quitó hace 300 millones de años — el ciclo funcionando al revés, y rápido.
Ejemplo 3: El océano contiene mucho más carbono que la atmósfera, por eso un cambio pequeño en cuánto absorbe importa tanto.
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